Separating intrinsic and domain-mediated anomalous Hall conductivity in Co3Sn2S2 via contact engineering

Abstract

Separating the momentum-space intrinsic Berry-curvature contribution to the anomalous Hall conductivity (AHC) from domain-mediated and extrinsic contributions in bulk ferromagnetic Weyl semimetals remains a central challenge. We address this via contact engineering in a ∼670 μm thick Co3Sn2S2 single crystal, where deep Ohmic contacts promote depth-distributed current flow without perturbing the bulk. Above ∼0.3 T, a single- or few-domain state exposes the intrinsic Berry-curvature response, with Callen–Callen scaling Ku/Ku(0)=[M/M(0)]n=2.258 holding below 120 K. Above 120 K, domain multiplication weakens the exchange splitting and magnetocrystalline anisotropy Ku, driving a sharp σxy crossover near 125 K. In low-field zero-field-cooled multidomain states, real-space Berry curvature and moderate extrinsic contributions sustain the Hall response up to ∼140 K. These results establish contact engineering as a noninvasive route for cleanly separating intrinsic from domain-mediated AHC in thick Weyl semimetal crystals.